• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.129-133
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• 1998

This paper deals with a characteristic of output for high frequency resonant inverter type x-ray generator in short exposure time. In the same tube-voltage, the waveform is stable in long exposure time (200msec) but more decreasing exposure time (50msec), the waveform is distorted. The ripple factor of tube-voltage waveform distorted more and more increase tube-voltage and in this case output is also unstable. High-frequency resonant inverter type X-ray generator using PSU source which introduced in resent is stable tube-voltage waveform and low ripple factor.

• Journal of Electrical Engineering and Technology
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• v.9 no.1
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• pp.286-292
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• 2014

This paper presents the parameters optimization technology for generating the first short stroke lightning current waveform($10/350{\mu}s$) which is necessary for the performance tests of components of lightning protection systems, as required under IEC 62305 and the newly amended IEC 62561. The circuit using the crowbar device specified in IEC 62305 was applied to generate the lightning current waveform. To find the proper parameters of the circuit is not easy because the circuit consists of two parts; circuit I, which relates to the front of current waveform, and circuit II, which relates to the tail. A simulation in PSpise was carried out to find main factors related to the front and tail of $10/350{\mu}s$. The lightning current generator was developed by utilizing the circuit parameters found in the simulation. In the result of experiments, new parameters of the circuits need to be changed because of the difference between the simulation and the experiment results. Using the iterative method, the optimized parameters of the circuits was determined. Also a multistage-type external coil and a damping resistor were proposed to make the efficiency of generation to enhance. According to the result in this paper, an optimized first short stroke lightning current waveform was obtained.

• The Journal of the Acoustical Society of Korea
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• v.20 no.2
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• pp.3-9
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• 2001

In this paper, a random number generator for simulation of speech-waveform coders was designed. A random number generator having a desired probability density function and a desired power spectral density is discussed and experimental results are presented. The technique is based on Sondhi algorithm which consists of a linear filter and a memoryless nonlinearity. Several methods of obtaining memoryless nonlinearities for some typical continuous distributions are discussed. Sondhi algorithm is analyzed in the time domain using the diagonal expansion of the bivariate Gaussian probability density function. It is shown that the Sondhi algorithm gives satisfactory results when the memoryless nonlinearity is given in an antisymmetric form as in uniform, Cauchy, binary and gamma distribution. It is shown that the Sondhi algorithm does not perform well when the corresponding memoryless nonlinearity cannot be obtained analytically as in Student-t and F distributions, and when the memoryless nonlinearity can not be expressed in an antisymmetric form as in chi-squared and lognormal distributions.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2152-2154
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• 1999

In this paper, we suggested the design rule of high-voltage rectangular waveform generator working in low frequency domain (5Hz $\sim$ 60Hz). Most of the commonly used power electronic switching devices have voltage ratings up to several kV. So it is difficult to design and fabricate high-voltage switching systems with the power electronic devices alone. We have combined IGBTC(1200V, 50A) with the specially designed transformer to get the high-voltage rectangular waveforms up to 40kV. In this work. next two things are the main factors. The first one is design of transformer working low-frequency domain close to 5Hz. And the second one is additional voltage source to floating the transformer voltage output. As a result, we can get frequency-variable and high-voltage rectangular voltage waveform and this can be a more efficient power source of sandpaper manufacturing process.

• Journal of the Semiconductor & Display Technology
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• v.20 no.3
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• pp.146-151
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• 2021

We introduce an arbitrary waveform generation method and its H/W implementation case based on Rademacher and Walsh function. According to the orthogonal and periodic features of Rademacher and Walsh function, simple calculations can generate arbitrary waves with affordable logics. We implemented an FPGA-based AWS using above two functions, and verified. HDL simulation shows the proposed idea can draw desired analog test waveforms very fast, and its H/W size is promising to Built-Out Self-Test(BOST) logics for AI ICs.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.1
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• pp.58-64
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• 2016

This study presents a design method for a single-loop voltage controller that is suitable for an arbitrary waveform generator (AWG). The voltage control algorithm of AWG should ensure high dynamic performance and should attain sufficient robustness to disturbances such as inverter nonlinearity, sensor noise, and load current. By analyzing the power circuit of AWG, control limitation and control target are presented to improve the dynamic performance of AWG. The proposed voltage control algorithm is composed of a single-loop output voltage control, an inverter current feedback term to improve transient response, and a load current feedforward term to prevent voltage distortion. The guideline for setting control gain is presented based on output filter parameters and digital time delay. The performance of the proposed algorithm is proven by experimental results through comparison with the conventional algorithm.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.181-184
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• 2005

Operating conditions of photovoltaic power generator is very sensitive to the PV modules. The PV module's control is an importance issue in the removing DC ripple noise. In this paper, the phase-shifted-carrier technique, which is a new three-step dc-dc power multi-converter schemes, is applied to solar generator system to improve the output current waveform. The novel type of three-step dc-dc converter presented has many features such as the good output waveform, high efficiency, low switching losses, low acoustic noise. The circuit configuration is constructed by the conventional full-bridge type converter circuit using the isolated DC power supply for which the solar cell is very suitable. In the end, a circuit design for understanding three-step dc-dc converter and new solar power system were presented

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.228.1-228.1
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• 2012

Digital waveform generation technology for SAR payload can be divided into DDS(Direct Digital Synthesizer) method and Memory Mapped(M/M) method. DDS is the single chip which consists of the Sine Table, NCO(Numerically Controlled Oscillator), DAC, and so on. DDS method is a very simple method because the circuit configuration is not complex but has a disadvantage that can not control phase and amplitude easily by using NCO. M/M method has the complexity of the circuit configuration because it requires the memories which stores the waveforms, the control circuits, and DAC. And this method should apply the high interface technology for being compatible with the wide bandwidth of the digital signal and has the difficulty for PCB design because the number of the signal lines should be increased according to the number of the data bits for DAC. Although it has several disadvantages, this method has the capability of pre-distortion function which can compensate the phase and amplitude characteristics of the system and also has an excellent advantage to make any arbitrary waveform, so this method is considered as an important technology with DDS method. This research describes the technological trends of the waveform generator for the SAR payload and analyzes the characteristics of the technology.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.260-265
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• 1996

The purpose of this study was to implemented a general purpose programmable nerve stimulator system as a research tool for studying psychophysiological performance associated with various stimulation waveform. This system is composed of hardware and software, the former are the personal computer(180586) and control unit(one-chip microprocessor, D/A converter, digital output), the latter are programmed in VISUAL BASIC and ASSEMBLY Which are programmed for the programmable nerve stimuli pattern editor and communication interface, waveform preprocessing, and stimuli generator. The control unit which is entrolled by the personal computer is capable of delivering the programmable nerve stimuli waveform. This system has research potential for determining the effect of various neuromuscular blockade in alternated physiological stat is.

• Journal of Korean Physical Therapy Science
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• v.30 no.3
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• pp.49-58
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• 2023

Background: This study aims to examine the useful- ness of the portable spirometer "The Spirokit" as a clinical diagnostic device through technology introduction, precision test, and correction. Design: Technical note Methods: "The Spirokit" was developed using a propeller-type flow rate and flow rate measurement method using infrared and light detection sensors. The level of agreement between the Pulmonary Waveform Generator and the measured values was checked to determine the precision of "The Spirokit", and the correction equation was included using the Pulmonary Waveform Generator software to correct the error range. The analysis was requested using the ATS 24/26 waveform recognized by the Ministry of Food and Drug Safety and the American Thoracic Society for the values of Forced Voluntary Capacity (FVC), Forced Expiratory Volume in 1second (FEV1), and Peak Expiratory Flow (PEF), which are used as major indicators for pulmonary function tests. All tests were repeated five times to derive an average value, and FVC and FEV1 presented accuracy and PEF presented accuracy as the result values. Results: FVC and FEV1 of 'The Spirokit' developed in this study showed accuracy within ± 3% of the error level in the ATS 24 waveform. The PEF value of 'The Spirokit' showed accuracy within the error level ± 12% of the ATS 26 waveform. Conclusion: Through the results of this study, the precision of 'The Spirokit' as a clinical diagnosis device was identified, and it was confirmed that it can be used as a portable pulmonary function test that can replace a spirometer.